ESP32-C3

Note

This document is automatically translated using AI. Please excuse any detailed errors. The official English version is still in progress.

ESP32-C3 Chip/Module Startup Conditions

The operating voltage range of the ESP32-C3 chip is 3.0 V ~ 3.6 V; when using a single power supply, it is recommended that the power supply voltage is 3.3 V, and the output current needs to reach 500 mA or more.
The operating voltage range of the ESP32-C3 module is 3.0 V ~ 3.6 V; when using a single power supply, it is recommended that the power supply voltage is 3.3 V, and the output current needs to reach 500 mA or more.
The CHIP_PU (EN) pin of the ESP32-C3 is the chip’s boot pin. When CHIP_PU (EN) is at a high level, the chip is enabled; when it is at a low level, the chip is turned off. Note: The CHIP_PU pin must not be left floating. When the ESP32-C3 is powered by a 3.3V system power supply, the CHIP_PU (EN) pin must be at a high level.

Hardware Wiring

The ESP32-C3 supports two firmware download methods: UART0 or USB.

When downloading firmware based on the ESP32-C3 module, for UART0, users need to prepare:

3.3V Power Supply
Serial debugging tool
Dupont wire

Proceed with the wiring as follows to meet the hardware requirements for chip power supply, power-on startup, and entering download mode.

ESP32-C3	3.3V External Power Supply	Serial debugging tool
3V3	VDD
GND	GND	GND
EN	VDD
GPIO2 (pull-up, default is floating)	VDD
GPIO8 (pull-up, default is floating)	VDD
GPIO9 (pull-down, default is weak pull-up)	GND
TXD0（GPIO21）		RXD
RXD0（GPIO20）		TXD

When downloading firmware based on the ESP32-C3 Module, users need to prepare:

3.3V Power Supply
USB cable
Dupont wire

Proceed with the wiring as follows to meet the hardware requirements for chip power supply, power-on startup, and entering download mode.

ESP32-C3	3.3V External Power Supply	USB cable
3V3	VDD
GND	GND	GND
EN	VDD
GPIO2 (pull-up, default is floating)	VDD
GPIO8 (pull-up, default is floating)	VDD
GPIO9 (pull-down, default is weak pull-up)	GND
GPIO18		USB_D- (White)
GPIO19		USB_D+ (Green)

Chip Power-On Startup Log

After powering on the ESP32-C3 chip/module, you can use the PC-side serial debugging software to view the UART0 serial output during chip power-up to confirm whether the chip has entered download mode. If the chip powers up and enters download mode, UART0 will print the following log:

ESP-ROM:esp32c3-api1-20210207
Build:Feb  7 2021
rst:0x1 (POWERON),boot:0x4 (DOWNLOAD(USB/UART0/1))
waiting for download

Note

After powering up the ESP32-C3 chip/module, if you do not see the log printing, you can trigger the log printing by pulling down and then pulling up the CHIP_PU (EN) pin for a hardware reset.

In terms of software, Espressif provides a PC-based Flash download tool, which can directly download firmware (.bin) into Flash. For usage instructions, refer to the Flash Download Tool User Guide.

After the firmware download is complete, if you want to run the burned firmware, you can pull up GPIO9 (default is high level) based on the aforementioned hardware wiring, and then pull down and pull up the CHIP_PU (EN) pin for hardware reset and restart, allowing the chip to re-enter the Flash boot mode. Finally, use the serial debugging software to view the UART0 log printout to check the firmware running status.

Note

The strapping combination of GPIO8 = 0 and GPIO9 = 0 is invalid and will trigger unexpected behavior.

When testing with the ESP32-C3-DevKitC-02 Development Board, you can directly use a USB Type-C cable to connect the UART or USB interface on the development board for firmware download. If you are using the USB interface to download the firmware for the first time, you need to manually pull down the GPIO9 pin, that is, hold down the Boot button and then power on, to manually enter the download mode.

Reference

Summary of Hardware Wiring Principles:

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